Potassium Hydroxide → Brequinar Analog

Participants

Reaction Steps

4-Phenylpropiophenone (18.9 g, 0.09 mole) and 5-fluoroisatin (20 g, 0.09 mole) were suspended in 360 ml of ethanol and stirred mechanically as a solution of 35.2 g KOH in 100 ml water was added dropwise over 15 minutes. The reaction mixture was heated at reflux for 12 hours, cooled, and the ethanol evaporated under reduced pressure. The resulting yellow solid was dissolved in water and washed with ethyl ether. The aqueous layer was cooled to 5° and acidified with glacial acetic acid. The resulting yellow precipitate was filtered and dried. Recrystallization from 200 ml of dimethylformamide and 25 ml water provided 13.8 g of 2-(4-biphenylyl)-6-fluoro-3-methylquinoline-4-carboxylic acid as a white solid, m.p. 303°-306°(d).

Provenance & Evidence